PURPOSE: To secure the use time of the portable terminal device, which is used frequently in a place wherein an external power source can not be secured, as an operator requires by securing a supply means for electric power.
CONSTITUTION: The portable terminal device is provided with connectors 25 and 26 to which plural battery packs 6 and 9 are connected, and the respective connectors are so structured that battery packs can be attached and detached independently of other connectors. The sockets are so wired that when one battery pack is detached, the other battery pack supplies electric power. Further, the sockets are wired across diodes 7 and 8 to prevent electric power from being transferred between the battery packs and also eliminates the potential difference between the individual battery packs.
NAKAMORI KIYOYUKI
YANAGIDA TOMOHIKO
NAGATA KOHEI
HITACHI ASAHI ELECTRON KK